From df82dbffb86244a9e4dae37717cb68a88b476fb5 Mon Sep 17 00:00:00 2001 From: Teresa Johnson Date: Tue, 18 Nov 2014 14:20:58 +0000 Subject: [PATCH] backport: re PR tree-optimization/63841 (Incorrect strlen optimization after complete unroll) 2014-11-18 Teresa Johnson Backport from mainline and gcc-4_9 branch. 2014-11-13 Teresa Johnson PR tree-optimization/63841 * tree-ssa-strlen.c (strlen_optimize_stmt): Ignore clobbers. 2014-11-13 Teresa Johnson PR tree-optimization/63841 * testsuite/g++.dg/tree-ssa/pr63841.C: New test. From-SVN: r217715 --- gcc/ChangeLog | 8 ++++++ gcc/testsuite/ChangeLog | 8 ++++++ gcc/testsuite/g++.dg/tree-ssa/pr63841.C | 35 +++++++++++++++++++++++++ gcc/tree-ssa-strlen.c | 2 +- 4 files changed, 52 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr63841.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3bb275bedd63..3bc25c3c2fae 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2014-11-18 Teresa Johnson + + Backport from mainline and gcc-4_9 branch. + 2014-11-13 Teresa Johnson + + PR tree-optimization/63841 + * tree-ssa-strlen.c (strlen_optimize_stmt): Ignore clobbers. + 2014-11-16 Eric Botcazou * doc/tm.texi.in (TARGET_FLAGS_REGNUM): Move around. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a4c8f412d847..1de0fd491868 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2014-11-18 Teresa Johnson + + Backport from mainline and gcc-4_9 branch. + 2014-11-13 Teresa Johnson + + PR tree-optimization/63841 + * g++.dg/tree-ssa/pr63841.C: New test. + 2014-11-12 Jakub Jelinek PR ipa/63838 diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr63841.C b/gcc/testsuite/g++.dg/tree-ssa/pr63841.C new file mode 100644 index 000000000000..2a2c78f9fb25 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr63841.C @@ -0,0 +1,35 @@ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +#include + +std::string __attribute__ ((noinline)) comp_test_write() { + std::string data; + + for (int i = 0; i < 2; ++i) { + char b = 1 >> (i * 8); + data.append(&b, 1); + } + + return data; +} + +std::string __attribute__ ((noinline)) comp_test_write_good() { + std::string data; + + char b; + for (int i = 0; i < 2; ++i) { + b = 1 >> (i * 8); + data.append(&b, 1); + } + + return data; +} + +int main() { + std::string good = comp_test_write_good(); + std::string bad = comp_test_write(); + + if (good != bad) + __builtin_abort (); +} diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index dbad4a80d867..fbd51ec2c980 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -1777,7 +1777,7 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi) break; } } - else if (is_gimple_assign (stmt)) + else if (is_gimple_assign (stmt) && !gimple_clobber_p (stmt)) { tree lhs = gimple_assign_lhs (stmt); -- 2.47.2